Surprised with a Friday night party at the Beverly Wilshire Hotel put on by his manager Scooter Braun and his mom Patti Mallette, Bieber spent the night with celebs including girlfriend Selena Gomez (who flew in from filming Spring Breakers in Florida), Kim Kardashian, Kylie and Kendall Jenner, Mike Tyson and others.

"He was all over Selena the whole time, walking her around by the hand. He kept kissing her," a source close to the pop star tells Us of his birthday PDA with Gomez, 19. "It's clear she was the best part of the night for him. He is still so in love with her."

In addition to his friends-and-family bash, Bieber also scored a one-of-a-kind Fisker Karma eco-friendly sportscar as a gift from Braun, with a reported pricetag of $102,000.